An ascorbic acid or a derivative thereof is well known to participate in the biosynthesis of collagen and have a function of keeping, particularly, skin in a firm and fresh state, preventing the production of a melanin pigment giving rise to spots and freckles, and maintaining a beautiful skin. However, when the ascorbic acid or a derivative thereof is formed into a lotion, a cream or the like for the application to skin, such a preparation is not coated in a constant amount to fail in providing a uniform effect or is removed from the skin due to contact with clothing to fail in providing a satisfactory effect.
In order to solve these problems, a method of incorporating an ascorbic acid or a derivative thereof into a hydrous gel having shape retentivity and applying the hydrous gel to skin is known. The hydrous gel used for a plastering agent or a cold insulator is usually constituted by using a natural water-soluble polymer such as tragacanth, acacia, carrageenan, duran gum, sodium alginate, mannan and gelatin, or a synthetic polymer such as polyacrylic acid, polymethacrylate, polyvinyl alcohol and polyacrylamide, as the base and blending therewith a humectant (e.g., polyhydric alcohol), water or the like. However, natural water-soluble polymers in particular are obtained from natural products and, therefore, are not stabilized in quality and, unless these polymers are purified to a higher level, a phenomenon such as contamination by an ingredient mingled or deterioration due to impurities is caused.
For example, Japanese Unexamined Patent Publication No. 2001-64175 (JP-A-2001-64175) discloses a method of preparing a hydrous gel containing an ascorbic acid or a derivative thereof by using two compounds out of magnesium metasilicate aluminate, dried aluminum hydroxide gel and aluminum chloride. This method is, however, insufficient for maintaining the shape retentivity of the gel. The hydrous gel undergoes sagging particularly in the summer season where the hydrous gel is exposed to high temperature, and a so-called strike-through is sometimes caused. Thus, there is still a problem to be solved.